Influence of pressures on the crystallization process of an amorphous Fe73.5Cu1Nb3Si13.5B9 alloy

Abstract

Amorphous Fe73.5Cu1Nb3Si13.5B9 alloys, prepared by a melt-spinning technique, were annealed at a temperature of 823 K under pressures in the range of 1–5 GPa and ambient pressure. The high pressure experiments were carried out in a belt-type pressure apparatus. The microstructure of the annealed alloys has been investigated by x-ray diffraction, electron diffraction, and transmission electron microscopy. Experimental results show that the initial crystalline phase in these annealed alloys is α-Fe solid solution (named as α-Fe phase below), and high pressure has a great influence on the crystallization process of the α-Fe phase. The grain size of the α-Fe phase decreases with the increase of pressure (P). The volume fraction of the α-Fe phase increases with increasing the pressure as the pressure is below 2 GPa, and then decreases (P>2 GPa). The mechanism for the effects of the high pressure on the crystallization process of amorphous Fe73.5Cu1Nb3Si13.5B9 alloy and latent applications of high-pressure annealing amorphous Fe73.5Cu1Nb3Si13.5B9 alloy have been discussed.

Synthesis, magnetic properties and magnetostriction of Pr(Fe0.75Co0.15Cu0.01Nb0.04B0.05)1.93 bulk nanocrystalline synthesized under high pressure

“…21,22 Considering the pressure and temperature dependence of average grain size, we can see that the coercivity i H c is inversely correlated with the average grain size in this system, indicating that the more grain refinement the less coercivity. Similar behaviors have been observed in some soft magnetic nanocrystalline and multilayer materials , such as Fe-Cu-Nb-Si-B system 13,20 and TbDyFe+Zr/Nb multilayer film. Table I.…”

“…The activation volume ∆V * is normally positive for amorphous alloys. 20 the atomic diffusion coefficient D will decrease with the increase in pressure and the decrease in temperature, resulting in a lower crystal growth rate during the crystallization process. As a whole, the easy nucleation and lower growth rate together give rise to the grain refinement.…”

Microstructures and soft magnetic properties of nanocrystalline Fe86B13Cu1 alloy annealed by hot isothermal pressing

“…Taking pressure (P) into account and assuming that the interfacial energy ( ) is independent of it, G * is given by [6][7][8][9] ∂( G * ) ∂P…”

“…Wang et al [6,7] reported that pressure affected the transformation behaviour of amorphous alloys significantly and often led to the formation of dense crystalline phase. Recently, we annealed amorphous Fe 86 Zr 7 B 6 Cu 1 ribbons by hot isothermal pressing (HIP) and found that a distinct improvement of the soft magnetic properties is induced by HIP [8,9].…”

Structure and magnetic properties of Ni5(Fe0.5Co0.5)68.5Si13.5Nb3B9Cu alloy

“…The crystalline volume fraction V cry is calculated from the XRD spectra according to [13] V cry ¼ I cry I cry þ I am ð1Þ…”